Flooring Attic.

[woodchopper]

What gap has to be left between the loft insulation and the flooring to be laid above it to avoid mould/condensation ?

[Buenchico]

See here:
https://insulation4less.co.uk/blogs/sc/boarding-a-loft-over-insulation

[Atheist]

If there is insulation between the horizontal ceiling joists of your current top floor, and if you then want to lay floorboards above that insulation to make the existing loft space usable as living accommodation, then you needn't worry about any gap above the insulation and the new floorboards. What matters is how you treat the new accommodation in what is now the existing loft. The new accommodation will need to be insulated (walls and roof), and that's a whole new story that you will need to research. I won't go into it because you have not made clear exactly what you want to achieve.

[Old_Geezer]

Well I've just learnt something new. Never occurred to me one needed to raise the floor. I guess those planks scattered around to hold stored items aren't ideal then.